The use of secure cards, for example, for processing of financial transactions, enabling secure network access, providing fast and reliable verification of a bearer's identity, and other purposes has become widespread. One example of such secure card is a card with a magnetic strip having a issuer-identifying code, user-identifying code, cipher data and the like, recorded thereon and readable by automated means. Furthermore, driven by the ever growing need for secure financial transactions, as well as more complex operations—combining, for example, payment and secure network access—conventional magnetic stripe cards are increasingly being phased out and replaced by so-called “smart cards,” i.e. laminated cards incorporating an integrated circuit or chip. The integrated circuit or chip typically includes a rewritable memory, and is configured to be energized by an external power supply and to exchange data with an external terminal when the card is inserted in the terminal. One non-limiting example of such smart card is described in U.S. Pat. No. 4,105,156, the disclosure of which is incorporated by reference herein.
Often, in addition to providing a banking card, access card, identification card, and the like with a magnetic stripe and/or chip for security purposes, as an additional security feature to hinder counterfeiters, such cards are also provided with a holographic image because such images are difficult to copy successfully. In addition, a hologram can be combined with a magnetic stripe for enhanced security, as described in U.S. Pat. No. 4,684,795, the disclosure of which is incorporated by reference herein.
As the secure card technology continues to gain momentum and card issuers seek to use its potential by delivering sophisticated solutions to establish closely tailored customer relationships, there is a strong demand for more attractive and distinctive cards that are aesthetically appealing to customers, as well as more effectively identify card issuers and promote their services.
Card manufacturers are responding to this demand by incorporating various visual effect layers, such as a metal foil layer, into the laminated card structure. Such a structure typically includes a core layer and at least one additional layer bonded thereto. U.S. Pat. No. 6,471,128 entitled “Method of Making a Foil Faced Financial Transaction Card Having Graphics Printed Thereon and Card Made Thereby,” incorporated by reference herein, demonstrates one such method of producing a laminated financial transaction card.
Known methods for manufacturing laminated cards having metal layers, such as, for example, split core process and the solid core process, suffer from several drawbacks. For example, as further explained below, these methods may result in a waste of expensive components and often require special safety precautions to address hazardous conditions inherent therein.
In particular, in a split-core process, a polymer-backed foil sheet, typically a metal layer bonded to a polyethylene terephthalate (“PET”) layer disposed over a polyvinylchloride (“PVC”) layer, is used as one of the core layers of the card. In order to balance the card and prevent undesirable warping induced by thermal expansion during subsequent steps of the manufacturing process, a layer of the same material as the backing layer of the foil sheet preferably is used as the other core layer of the card. In contrast, in the solid core process, the foil sheet is bonded to one surface of a solid opaque core. However, as in the split-core process described above, to balance the card and prevent warping, a layer of the same material as the backing layer of the foil sheet preferably is bonded to the other surface of the core. In both of these methods, costs of the materials can be rather substantial, and as a result, such cards are typically several times more expensive to manufacture than conventional cards. Using more rigid and less expensive materials, such as polyvinylchloride (“PVC”) instead of the material of the backing layer of the foil sheet may reduce the materials cost, but also increases the probability of warping and resulting waste.
Furthermore, in the methods described above, imaging, i.e., creating graphic images and/or alpha-numerical symbols, is carried out on relatively expensive materials, i.e., the metal layer of the foil sheet having an additional image receptive coating thereon and/or the backing layer of the foil sheet, e.g. PET. Imaging on expensive materials is undesirable given the substantial amount of waste typically involved in the imaging process.
Also, certain aspects of known methods for manufacturing laminated cards with metal layers may be hazardous and require proper precautions. For example, if a solvent silkscreen press is used to create images on the foil sheets, there is substantial risk of curling stock in the hot air dryer, which may result in equipment jams, and worse yet, fires caused by the backup of the foil sheets in the dryer. Finally, in order to have aesthetic and/or functional features visible from both sides of the card, it is known to include metal layers on both sides of the polymer core. Because such structures include two conductors in the form of two metal layers that are separated by a polymer insulator, they may operate as capacitors accumulating a static charge each time the card is used. Potential electrostatic discharge from these cards may damage the processing equipment
Thus, there remains a need in the art for multi-layer secure cards, e.g., banking, access, or identification cards, that include aesthetic and/or functional features to satisfy the demands of the card issuers, while being less expensive and safer to manufacture.